Virus-based bionanotechnology holds the promise of control over the structure, properties and functionality of materials at the nanometre scale. After all, viruses, and by extension virus-like particles (VLPs), represent some of the largest hierarchical protein constructs found in Nature. Their symmetrical architecture and their high degree of monodispersity, compared with other nanoparticles, make them unique as nanobuilding blocks. Furthermore, many of these particles seem to have specific and tuneable physical properties that can be utilized for their further function and manipulation. Viruses and VLPs are therefore highly desirable nanobuilding blocks that could find applications ranging from nanocontainers, for studying reactions in confinement or drug delivery, to modular structural components, that allow for the creation of complex nanoarchitectures, and eventually functional materials. This chapter is intended to generate an understanding of how the structure, modification and organization of viruses enable them to be the key component in these potential, functional materials, a field recently introduced as chemical virology. Ultimately, these functional virus-based materials could allow the construction of novel optical, electronic, catalytic, imaging and other nano-scale precision-based applications.